I can't think of a sheep breed which has that lovely rich dark red you are looking for, but you might get it by dyeing a moorit Shetland, Castlemilk Moorit , moorit type Soay fleece or even a reddish brown alpaca with madder and alum, or cochineal (I don't like the idea of crushing all those little insect bodies
). I think Ladies Bedstraw root also gives a red if you can find enough and dig it up....
When you choose your coloured specimen sheep, don't forget to include a Blue Texel which gives a lovely steely blue/grey. Oh, you would have such fun choosing just which animals to keep. I used to have a 'fleece flock' of various breeds and crosses, all wethers, whose fleeces pleased me. Sadly long gone now.